不同施肥水平下宝鸡旱塬连作冬小麦产量与深层土壤水分效应的模拟研究

Simulation of yield and deep soil water effects of winter wheat field under different fertilization levels in Baoji dry-land of the Loess Plateau

【目的】探寻与黄土高原半湿润区降水状况相适应的、有利于土壤水分可持续利用的合理施肥水平,为当地小麦生产的可持续发展提供科学依据。【方法】在模拟精度验证的基础上,应用侵蚀和生产力影响计算模型（WinEPIC模型）模拟研究了黄土高原半湿润区宝鸡旱塬1961-2000年无肥（N0 kg/hm^2,P 0 kg/hm^2）、低肥（N90kg/hm^2,P 30 kg/hm^2）、中肥（N 120 kg/hm^2,P 60 kg/hm^2）、高肥（N 150 kg/hm^2,P 75 kg/hm^2）和超高（N 180kg/hm^2,P 90 kg/hm^2）肥力处理5种施肥水平下,连作冬小麦的产量变化和深层土壤的水分效应。【结果】无肥、低肥、中肥、高肥和超高肥处理下1961-2000年宝鸡旱塬冬小麦的产量均呈波动性降低的趋势,其平均值分别为1.588,2.306,3.327,3.981和4.764 t/hm^2;连作冬小麦逐月土壤有效含水量也均呈波动性降低趋势,5种施肥处理的年均土壤干燥化速率分别为11.4,11.6,14.9,14.9和18.2 mm/a。在5种施肥条件下,模拟期间均出现了土壤干燥化现象,在5-16年都形成了相对稳定的土壤干层,其中无肥和低肥处理的土壤干层分布于2-3 m土层,中肥和高肥处理分布于2-4 m土层,超高肥处理分布于2-5 m土层。【结论】随肥力和作物产量水平的提高,作物耗水量增大,土壤干层厚度逐渐加深。宝鸡旱塬连作冬小麦适宜的施肥量为N120-150 kg/hm^2,P 60-75 kg/hm^2。

[Objective] The experiment was to provide scientific basis for sustainable development of local wheat production,which was fit for the fertilization levels adaptive to precipitation condition of the semi-humid area of Loess Plateau as well as beneficial to soil water sustainable utilization. [Method] Based on model validation,the WinEPIC model was used to simulate yield and deep soil water effects of continuous winter wheat under 5 fertilization treatments in Baoji semi-humid area of the Loess Plateau. [Result] Grain yield of the continuous winter wheat under no fertilization,low fertilization,medium fertilization and high fertilization treatment decreased significantly with fluctuation, average yield was 1. 588,2. 306,3. 327, 3. 981 and 4. 764 t/hm^2 respectively; Simulated monthly available soil water content of all 5 fertilization treatments declined with annual and seasonal fluctuations,average annual soil desiccated rate was 11.4, 11.6,14.9,14.9 and 18.2 mm/a respectively; soil desiccation and stable desiccated soil layers of all 5 fertilization treatments occurred after 5-16 years of continuous cropping simulation. Distribution depth of dried soil layers was 2-3 m of no fertilization and low fertilization treatment,2-4 m of medium and high fertilization treatments,2-5 m of superhigh fertilization treatment respectively. [Conclusion] As fertilization and crop yield increased,dried soil layers were thickened and crops water consumption was increased. The suitable fertilization level of Baoji dry-land was N 120-150 kg/hm^2,P 60-75 kg/hm^2.